I'm a youngster-at-heart in my "early 60's" and just started receiving my Social Security benefits. I bought my '06 Z4 M Roadster in July and drove a Honda S2000 for 13 years before that. I'm planning on European Delivery of an M4 in 2016, not sure what I'll buy after that.

Welcome to the wonderful world of BMW! Wikipedia will give you a full history of all BMW models. Unfortunately you have arrived to this world just as BMW is offering more and more models with even more distinct chassis codes, so it may take a little more time to figure out all the current and upcoming models. We're also in the middle of the 3/4 Series changeover, so if you wanted a new 3 Series Sedan it will be an F30 while a 3 Series Coupe will still be an E92. Fast forward six months and the 3 Series Coupe will not exist, it will be a 4 Series F32.

All you have to know right now is that you have a 3 Series E90 328xi if you own a Sedan and a 3 Series E92 328xi if you own a Coupe.